Bits, Bytes, and Download Time Estimates 指南

本指南說明 Estimate why internet speed, file size, and storage labels can use different data units.

指南更新 2026-05-11

使用流程

Use this guide when a converted number affects downloads, backups, cloud storage, video files, and network speed checks. A reliable result keeps the original value, source unit, target unit, conversion factor, and rounding choice visible.

The goal is not to memorize every factor. The goal is to make the calculation traceable enough that someone else can review it later.

檢查清單

Remember that network speeds usually use bits per second.
File sizes usually use bytes, so divide bits by eight before comparing.
Check whether a tool uses decimal GB or binary GiB.

實用事實

A capital B usually means byte, while a lowercase b usually means bit.

實用範例

100 Mbps is about 12.5 MB/s before overhead.

4 GB at 100 Mbps takes at least about 5.3 minutes.

1 byte equals 8 bits.

常見問題

What should I check first?

Confirm the source unit and target unit before changing the number.

When should I round?

Round at the end, after formulas and related conversions are complete.

Which calculator should I use next?

Use the related calculators below to check the main values from this guide.

重點

A useful conversion is traceable: it shows the original unit, the target unit, the factor used, and the rounding decision.